Flexible tube pump



Dec.

l.. E. HARPER FLEXIBLE TUBE PUMP 2 Sheets-Sheet l Filed Deo. 51, 1943 llNvEm-on LYNoua E. HARPER ATTORNEY De- 10,1946- L. E. HARPER 2,412,397

FLEXIBLE TUBE PUMP v l Filed Decfsl, 1943 2 Sheets-sheet 2 5s a1 i?) v59 s 5:5 sa eo 56 l 3l xNvENToR LYNDUS E. lHARPER WW/ECL, A

ATTORNEY Patented Dee...1o, ,194e

UNITED 'STATES' l PATENT, OFFICE nauwer, um city. M0. l Appuull member31, 1943, SOIN N0. 516,399 l I 1 My invention relates to pumps, and moreparticularly to a-iiexible tube pump.

It is a purpose of my'invention to provide a pump that comprises aflexible walled Dump chamber, with which is associated a flexible walledinlet valve and a flexible walled outlet valve, and means forcompressing or squeezing the walls of said valves and said pump chamberto obtain a movement of fluid from an inlet connection to a dischargeconnection. Preferably, said flexible walled valve means andpump'chamber are all incorporated in a sin- 81e ilexible walled tubularmember. Said ilexi-ble walled tubular member is made of resilientmaterial, such as rubber, or the synthetic equivalent thereof, or anysimilar tubular member that will have the quality of a thick walledrubber tube of returning to its original contour after havin beendeformed.

It is a particular Purpose of my invention to provide a device of theabove mentioned character, in which the means for squeezing or com--pressing the tubular member to seal on portions thereof to provide inletand outlet valve means and for varying the capacity of a portion thereofto produce a pumping action, has a simple compressingl action on thetubular member by a movement transversely of the length thereof, withoutany longitudinal component'to such movement, to thus overcome objectionsto pumping devices which have been previously provided, that utilizeexible tubular members to obtain a pumping action, in which means forsqueezing the walls of the tube together have a movement lengthwise ofthe tubular member, always in the same direction, which tends to causethe tubular member to be stretched and the material thereof to flow inthe direction of movement of said squeezing means, thus causing saidmaterial to bunch up at a certain point, and reducing the thickness ofthe wall of the tubular member at all other points to thus shorten thelife thereof.

The above referred to purpose of my invention l is accomplished,preferably, by means of followers, which cooperate with ca m means tomove in a direction transversely of the length of or substantiallytransversely of the length of the tubular member to bring about thepumping action through operation ofthe valve means and the pumping meansthus provided. Said cam means may constitute a cam for each of saidfollowers or a single cam for all of the followers.

It is a purpose of my invention to provide a pump of the above mentionedcharacter having a body portion that has a passage therein, within 1eclaims. (ci. 10s-14s) 2 which the flexible tubular member having theresilient walls is conilned, and to make the passage of such crosssectional size andshape that the same will accommodate the tube when itis squeezed ,or distorted out of the substantially circular crosssectional contour.

It is another purpose of my invention to provide a pump of the abovementioned characterthat can be adjusted so as to pump any desiredquantity of fluid in a given period of time that it maybe desired topump therethrough, this being accomplished by either varying the speedof -rotation of the cam or drive shaft, or by providing means forlimiting the movement of the follower or tube compressing member thatvaries the capacity of the pumping chamber. v

An important feature of the `invention is that it can be used tointroducematerial to the suc-- tion side of a larger pump and materialwill'not now through the pump forming the subject matter of thisinvention, due to the suction created Aby the larger pump. Similarly,the pump can be used to introduce materials into 'any line in whichthere is a partial vacuum or suction and at. no time willthere be anymore material pass through the pump forming the subject matter of thisin-` vention than the same is intended to pump in accordance with theadjustment thereof. The pump can be operated either at a very slow rateor at a high rate of speed, as may be found desirable, and can b'e madewith the tubular member of very small bore and also of large bore sothat pumps of either small or large capacity, or

in face of any capacity, can be built in accordance with my invention.

My pump is particularly adapted for supplying small quantities of fluidmaterial, such as liquid, to larger bodies of liquid, and can beutilized, for

example, for introducing'small quantities of water` purifying or similarmaterial into a larger supply of water in the exact proportion desired,by providing a water meter in the pipe through which flows the water towhich the treating or dosing material is to be supplied, and driving myimproved pump directly from the drive shaft of` the water meter to thusmaintain the proportion of purifying material to the quantity of Waterpassing through the meter in accordance with particular details shown ordescribed, except as defined in the claims.

In the drawings: Y

Fig. 1 is a transverse sectional view through A my improved pump, thedrive shaft being brolien away.

Fig. 2 is a section Fig. 1.

Fig. 3 is a section taken on the line of Fig. 1.

` Fig. 4 is a section taken on the line 4--4 of Fig. '1. I

Fig. 5 is a top plan view of a modified form of pump, the cover platebeing removed.

Fig. 6 is a transverse sectional view of the pump shown in Fig. 5, thesection being taken on'a plane lcorresponding to the line 6-6 of Fig. 5,but the cover plate being shown in position, and l Fig. 7 is afragmentary sectionalview taken on the line l--`| of Fig. 5, but showingthe cover plate in place. A

Referring in detail to the drawings, in the 20 form of the inventionshown in Figs. 1 to` 4, inclusive, the pump comprises a body portion "I,which is shown as being made of two similar halves 8 and 9, which aresecured together in any desired manner so as to be held inl relativelyfixed position. The two halves of said body portion are provided withchannels or grooves therein to form a passage I0 therethrough, which issomewhat deeper than it is wide, vas shown in the drawings, the width ofthe passage I0 being substantially that of a flexible 'tubular memberII, which is, preferably, made of resilient material, such as rubber, ora synthetic material of a similar character to rubber, vor any similarina-,- terial that has suiicient elasticity to return to 35 its originalshape after having been distorted out of such shape by applying pressurethereto.

'The channel -I0 is, preferably, provided with an annular'groove I2 andan annular groove I3 in the wall thereof, in which the annular ribs I440 and I5 of the inlet connection I6 and outlet connection Il,respectively, are mounted. The inlet connection and outlet connectionhave reduced Aend portions I8 and I3, respectively, received within thetubular member II, and to which the 45 tubular member II is clampedbythe cooperating halves 8 and 9 of the body portion, which have thechannels therein so shaped as to provide a substantially cylindrical orcircular por` from the inner end of the inlet connection to the innerend of the outlet connection is, however, preferably rectangular oroblong in cross section, as will be obvious from Figs. 3 and 4.

. Said body portion made up of the members 8 and 9 is also provided withsuitable channels to provide a passage for the drive shaft or cam shaft22,v and recesses for accommodating the 'cams provided on said shaft.Said portions 8 65 and 9 of the pump body may be provided'with channelstherein to provide the bearing portions 23, 24, 25 and 26 for saidshaft, or if desired,

'separate bearings for the shaft can be mounted in recesses, provided insaid members to accom- 70 modate said separate bearings, and secured toone thereof.- `The body portion is further provided with suitablechannels in the halves 8 and 9 thereof to provide passages 21, 28 and23, which serve as guides for reciprocable followers -to be I5 taken onthe line 2-2 of 5- described below. The

vThe shaft 22 is provided with a cam 30, which l engages a follower 3|,a cam 32 'that engages a follower 33, and a cam 34 that engages afollower 35. The body of the pump made up of the portions 8 and 3 isprovided with suitable recesses,

therein to accommodate the cams 30, 32 and 34, these recesses beingdesignated by the numerals 36, 31 and 38, respectively.Y 'Ihe cam 30 isprovided with a high portion 33, the cam 32 with a high portion 40 andthe cam 34 with aA high portion 4|.

When the high portion of the cam 39 is in engagement with the follower3| the tubular member Il is compressed between the end 42 of saidfollower 3| in engagement therewith and the wall of the passage so thatthe same will be squeezed or distortedto seal the passage 43 normallyexisting in said tubular member II, the passage being closed then, asindicated at 43' in Fig. 2. The portion of the tubular member engaged bythe follower 3| in cooperation with said follower has been completed andthe discharge stroke of follower in engagement with said tubular member||,does not commence until the follower 3| has reached the positionshown in Fig.A 2.

Similarly, the high portion 4| of the cam 34 is of such arcuate lengthrelative to the high portion 39 of the cam 30 and the high portion 40 ofthe cam 32, that the follower will be in engagement with the low portionof the cam 34 at the time that the' movement of the follower 33 in adirection to compress the tubular member` I begins, said follower 35incooperation with the portion of the tubular member |I engaged therebyconstituting the discharge or outlet valve of the pump, which will' thenbe wide open to permit discharge of the uid in the pump cham'- berformed by the portion of the tubular `mem-- ber opposite the follower 33to pass out through the same into the discharge or4 outlet connectionI1. Said high portion 4| of the cam 34 is further of such arcuate lengthand so disposed relative to the high portion 40 of the cam 32 that thesame will move the4 follower 35 so as to compress the tubular memberbetween the end thereof engaging said tubular member II and the wall ofthe passage I0 Opposite thereto, to close the passage 43 in the mannerillustrated in Fig. 2, after the follower 33 hasl completed its movementtoward the wall ofthe passage lllopposite thereto and while the highportion 40 of said cam 32 is in engagement with said follower. Furtherthe high portion 39 of the cam 30 is of such arcuate length and sodisposed that it will pass from engagement with the follower 3| and saidfollower will be in engagement with the low portion of said cam beforesaid high portion 40 of the cam 32 leaves the follower body portions 8andl 9 f may be made of any suitable material, such as 33, the inletvalve thus opening before the foilower 33 begins its return stroke,which constitutes the suction or intake stroke of the pump.

The inherent resiliency. of the tubular member Il will cause thefollowers to remain in contactv trolling the rate of rotation of saidshaft. In-

mmgaaeaiidmn l for the shaft 52, upon which a single cam 53 is mounted.Said body portion 5ll" is provided with a passage 54 therein, havingstraight portions 51, 58 and 59 that are substantially rectangular incrossv section and, preferably, of greater depth than width, the widththereof being subaddition to this, or instead of this, means-can beprovided for controlling the amount of ma- A terial pumped per stroke ofthe pump by suitable stroke adjusting means to be described below.

stantially .that of thel externaldiameterfofthe tubular member 55, whichis similar to the tubular member Il, previously described. Said passage54 has curved'portions 56v connecting the Qstraight passage portion 58with the straight Preferably, said stroke adjusting means comprisesadjustable stop means for limiting return movement of the follower 33,as -in that manner the stroke of the pump and the quantity of materialpumped on each stroke can be controlled,

as obviously if the follower 33 does not return to the position shown inFigs. 1 and 3, the capacity of the portion of the passage 43constituting the Dump chamber of variable capacity bymeans of saidfollower 33 will not be at its maximum. While the follower 33 willcompress or squeeze the tubular member Il against the wallof the passageportions 51 and 59. The curved portions 56 of .said passage are circularin cross section and, preferably, closely iitA the tube 55, as shown inFig. '1.Y The body portion 56 also has passages i 60 vand 6Itherein,fwhich. extend substantially. transversely to the .straightportions 51 and 58 of the 'passage 54, which these intersect, and theseextend substantially radially from the axis of the shaft 52..

I0 so as to close the same throughout the length thereof opposite theface 44 of said follower 33,

'- or distorted to substantially the shape of said tubular memberrsownlin Fig. 2, when the limit of the stroke of t e follower 33, due toengagement with the high@V portion of the cam is reached,

the amount of material pumped by such action of the follower will bedependent upon the size to which the passage 43 is permitted to expandwhen the follower moves away from the wallof the passage I8 due to thehigh portion 40 of the cam leaving the same. While the adjustable stopmeans for limiting this return movement,

A recess 62 is provided in the body portion 56, suiciently large toreadily accommodate the cam 53 and the passages 60and 6I extend fromsaid recess to the passage 54. A wide rectangular recess 53 is connectedwith the recess 62 by a wide passage 64. The cam has a singlesemi-circular high portion 65 and a semi-elliptical low portion 66, saidhigh and low portions being so related to the followers 51, 69 and 68slidably mounted in the passages 68 and 6I and in the recess 63 thatsaid followers will operate in proper se quen'ce to compress or squeezethe'tubular inem- .b'er 55 into engagementv with the wall of thestraight portion 51` of the passage 54 close the *inlet valve formed bymeans of the follower 61 l and the cooperating portion of the tubularmemt ber 55 before the follower 68 begins to compress j 4o and thusthe'lcapacity of the pump chamber, may j be of any desired character,and may be provided with any suitable means for indicating theadjustment/thereof, a simple form -of such stop means may be such asshown in Fig. 3, in which an adjustable stop screw 46 isscrew-threadedly mounted in the upper member 9 of the body por.- tion 1,the head portion 41 thereof being mounted in a recess 48 therein.Rotation of the screw or. squeeze the tubular member 55, and lto retractthe follower 59 so as to open the outlet valve formedby said followerand the cooperating portion of the tubular member 55 before'saidsqueezing or compressing action of the follower commences, andconversely tol close the outlet valvey by means of the follower`69 andopen the inlet valve by means ofthe follower` 51 before the reengagetherewith, and which can in a similar manner be distorted to pump liquidmaterial therethrough by means of the follower 33, can be utilized aslong as said material has an inherent resiliency or elasticity, suchthat it will tend to return to its normal shape of circular crosssection, or any other desired cross section,

in which the passage through the same has its maximum capacity, upon thesqueezing pressure exerted thereon by the followers being relieved.

Instead of providing a pump with a straight passage through the same forthetubular member and a plurality of cams for operating the followers toaccomplish the pumping action, my improved pump can be made in the formshown screw 18 also has a nut-like locking member 86 the high portion 65of the cam disengaging the roller 10 on the follower 68.

Suitable means is provided for adjusting the stroke of the follower 68to any desired length to pump the desired quantity of fluid material perstroke of said follower. The follower 68 is, preferably, provided with apartially cylindrical re cess 1| in which the roller 10 is seated. Saidroller ismounted on va depending shaft-like or pivot portion 12 of aslide.13 mounted for reciprocation in a passage. 14 in the cover member15 xed to the body portion 50 to complete the pump body. Said covermember is also provided with a recess 16 to accommodate the dependingmember 12 in its lmovements with the follower 68. The slide 13 has adepending bracket portion 11 provided' with a threaded openingforreceiving the adjustable stop screw 18 having a knurled head 19thereon for adjusting the same. The

thereon having a finger piece thereon for adjusting the same. Said screwcan be adjusted to limit the return movementof the follower 64,

said screw thus serving as adjustable stop means for the follower.

Any suitable means may be provided for driving the shaft 52, but,preferably, means is prowhich thevniain iscr- .'tion 56 of the pump isprovided with a, bearing 'ana-fsa? 2 7 a vided the speed of which isvadjustable. z One of the desirable applications of a pump of thecharacter shown in Fig. 5 is to supply small quantities of dosingmaterial, such as water purifying material, to a larger quantity ofliquid in proper proportion, such as to water for softening or purifyingthe same, and in such case it is highly desirable to operate the shaft52 at speeds in proportion to the amount of water that is to bevtreated. This can be readily accomplished by connecting the shaft 52with the shaftv 8| of a water' meter 82 by means of any suitable means,such as the which seats on the water meter and is bolted thereto bymeans of the bolts 81, said body portion having a slight offset thereinat 88 to seat in the ledge usually provided for the removable top of thewater meter.

Screw-threaded openingsV 89 may be provided in the body portion 50 forfastening said body portion to any suitable base or bracket, or othermeans for mounting the same by means of screwthreaded headed members ofany-suitable character. Said pumping means can be made of such smallsize that the same can be readily driven by a water meter proportionateto the rate of rotation of said meter, and thus proportionate to therate at which the water passes through a conduit or pipe in which themeter is interposed, without in any manner interfering with theoperation of the water meter. Preferably the tubular member 55 passesfrom the passage 54 out of the pump body through enlarged end portions90 of said passage, provided to clamp spiral stiiening members 9|between said tubular member 55 and the walls thereof to holdsaid-stiffening members in posi` tion to prevent any kinking of saidflexible tubular member 55 where it passes from the pump body.

It will be `noted that in both forms of the inven tion the ends of thefollowers are provided with rounded contours so as to avoid sharpcorners that might cut or sharply bend or crease the resilientdeformable tube to avoid injury thereto.

What I claim is:

1. In a. pump of the character described, a flexible tubular member, aninlet conduit leading into one end thereof, a discharge conduit leadingfrom the other end thereof, reciprocable means for sealing od a portionof said tubular member from said inlet conduit, reciprocable meansspaced therefrom for sealing olf a portion of said ltubular member fromsaid discharge conduit, reciprocable means engaging said tubular memberto 'alternately decrease and increase the capacity thereof between saidsealing means, driven means for reciprocating said means in relativesuccession to move a iiuid from said inlet conduit to Said dischargeconduit through said exible tubular member, and means for adjusting `theamplitude of movement of said reciprocable.

capacity varying means.

2. In a pump of the character described, a'

flexible tubular member, an inlet conduit leading into one end thereof,a discharge conduit leading from the lother end thereof, means forsealingV discharge conduit, reciprocable means engaging said tubularmember to alternately decrease and i Lbody portion having a continuouspassage of substantially uniform cross section therein, a.

Y. exible tubular member, an inlet conduit leading into one end thereof,a discharge conduit leading from the other end thereof, meanscooperating with the wall of said passage to deform a predeterminedportion of said tubular member'to sage to seal said member at saidstation, meansv at a predetermined' station between said other. end ofsaid tubular member and said deforming means cooperating with the wallof said passage to seal said member at said last mentioned station,means for movingsaid deforming means and said sealing means toward .andawayfrom said wall in relative succession to move a fluid from saidinlet conduit to said discharge conduit through said tubular member, andmeans for limiting the amplitude of movement of said deforming means.

4. In a pump of the character described, a body portion having a passagetherethrough, a flexible. tubular member' having an unobstructedvpassage therethrough mounted in said passage, an inlet connectionleading into one end of said tubular member, a discharge connectionleading out of the other end thereof, a plurality of followers mountedfor reciprocation in said body portion each engaging said tubular memberat one `end thereof, a

shaft, and asingle cam on said shaft* engagingA said followers tosuccessively vmove the same into engagement with said tubular member tomove flexible tubular member mounted in said passage,

' an inlet connection leading into one end of said tubular member, adischarge connection leading out of the other end thereof, a pluralityof followers mounted for reciprocation in said body portion transverselyof saidpassageeach engaging said tubular member 'to squeeze the samebetween said followers and the wall of said passage, rotatable meansengaging said followers tomove the same into squeezing engagement withsaid tubular member, and adjustable means for limiting the reciprocatingmovement of one of said followers. k

6. In a pump ofthe character described, abody portion having acontinuous passage of substan- -tially uniform cross sectiontherethrough, a flexible tubular member mounted in said passage, aninlet connection 'leading into one end of said tubular member, adischarge connection leading out of the other end thereof, an inletvalve comprising a blunt ended follower mounted forreciprocation in saidbody portion transversely of said passage to engage the blunt endthereof with said tubular member, an outlet valve comprising a bluntended follower mounted for re- `ciprocation in said body portiontransversely of `saidpassage to engage the blunt end thereof withsaidtubular member in spaced relation to said inlet valve follower, awide, fiat faced reciprocable vmember mounted to engage said tubularmember between said followers to vary the capacity of the portion ofsaid tubular member engaged thereby,

and means for reciprocating said followers to/ squeeze said tubularmember between the same and wall portions of said passage to seal saidtubular member and said reciprocable member to alternately decrease andincrease the capacity of said portion of said tubular member in suchorder as to pump a iiuid through said tubular member from saidinletconnection to. said discharge connection.

'7. In apump of the character described, a body portion having a passagetherein, a flexible tubular memberl mounted in said passage, an inlet atone end thereof, an outlet at the otherend thereof, reciprocable meansfor sealing off a portion of said tubular member from` said inlet,reciprocable means spaced therefrom for sealing off a portion of saidtubular member from said outlet, reciprocable means engaging saidtubular member to alternately decrease and increase the capacity thereofbetween said sealing means, and driven means for reciprocating saidmeans in relativeysuccession to move a fluid from said inlet to saidoutlet through said exible tubular member, said tubular member lo malcross sectional shape having an unobstructed passagev of a definednormal cross sectional area therethrough, inlet valve means and outletvalve means engaging said tubular member at spaced points to controlflow of fluid therethrough, a reciprocable member engaging said ltubularmember between said inlet valve means and said outlet valve means toalternately decrease and increase the capacity of the 'portion thereofbetween said valve means, driven means for operating said valve meansand said member in such relative succession that duid enters saidportion of said tubular member through said inlet valve means and isdischarged through lsaid outletvalve means, and means for adjusting thestroke of said reciprocable member.

11. In a Dump of the character described, a`

body portion having a continuous passage of substantially uniform crosssection therethrough being normally of substantially circular cross vinto said pump through said inlet valve means and discharge, it throughsaid discharge valve l means, and means for adjusting the stroke of oneof said squeezing means to control the quantity of fluid passing throughsaid pump during one cycle of operation'thereof.

9. In a pump of the character described, a exible tubular member of apredetermined normal cross sectional shape having a uniform passage of adened normal cross sectional area therethrough free of obstructionstherein, a housing through which said tubular member extends, inletvalve means and outlet valve means engaging said tubular member atspaced pointsA in said housing to control ow of fluid therethrough, amember reciprocable in said housing having a blunt end engaging saidtubular memlet valve means to alternately decrease and increase thecapacity of the portion thereof `between said valve means, and drivenmeans for operating said valve means and said member in such relativesuccession that uid enters said portion of said tubular memberthroughsaid inlet valve meansand is discharged through said outlet valvemeans, said means positively moving said reciprocable member in capacitydecreasing direction, vsaid tubular member having the inherent tendencyto return to normal cross sectional shape upon deformation thereof tomove said reciprocable member in capacity increasing direction.

10. In a pump of the character described, a flexible tubular member of apredetermined norber between said inlet valve means and said outfree ofobstructions therein, a flexible tubular member mounted in said passage,said tubularmember having the inherent tendency to resume its normalcross sectional shape upon distortion thereof, a plurality of followersmounted `for`reciprocation in said body portion each engaging saidtubular member at one end thereof to squeeze the same solely betweenitself and a wall portion of said passage, a shaft, and cam means onsaid shaft engaging the other ends of said followers to successivelypositively move the same into squeezing engagement with said tubu f larmember and to permit movement of said folf lowers in a return directiondue to the tendency s v of said tubular member to return to its normalshape to move a fluid tnrough the same in a pre f determined direction.

1.2. In a pump of the character described a body portion having a shaftmounted therein, a single cam Iori said shaft, said body portion hav-`ing a continuous passage extending around said cam in spaced relationthereto and having spaced end portions, a flexible tubular membermounted in said passage with the ends thereof `projecting from said bodyportion at the ends of said passage, and means actuated by said camreciprocable in said body portion and engaging -said tubular member tosuccessively squeeze the walls of the same together between saidreciprocable means and awall of said passage, said reciprocable meanscomprisingr inlet and discharge valve means spaced along said passageand a member that alternately decreases and increases the capacity ofsaid tubular member between said valve means having a blunt end engagingsaid tubular member.

13. In a pump of the-character described a body portion Vhaving a shaftmounted therein, a' single cam on said shaft, said body portion having acontinuous passage extending around said cam in spaced relation theretoand having spaced end portions, a flexible tubular member mounted insaid passage with the ends thereof projecting from said body portion atthe ends of said passage, means actuated by said cam reciprocable insaid body portion and engaging said tubular member to successivelysqueeze the walls of the same together between said reciprocable meansand a wall of said passage, said reciprocable means comprising inletand' discharge valve means spaced along said passage and a member thatalternately decreases and increases the capacity of said tubllar memberbetween said valve means having a blunt end engaging said tubularmember, and means for adiustingthe stroke of said capacity varyingreciprocable member.

14. In a pump of the character described, a flexible tubular member ofapredetermined normal cross sectional shape having an unobstructed passae of a dened normal luniform cross secg housing through` tional areatherethrough, a which said vtubular member extends, inlet valve anasev vwall of. said passage. said reciprocable means means and outlet valve`means engaging said y tubular member at spaced points in said housing tocontrol fiow of fluid therethrough, a member reciprocable in saidhousing having a blunt end engaging said tubular member between saidinlet valve means and said outlet valve means to alternately decreaseand increase the capacity of the portion thereof between said valvemeans, and a single cam for operating said valve means and said memberin such relative succession that iluid enters said portion of saidtubular member through said inlet valve means and is discharged throughsaid outlet valve means without inating said portion and withoutincreasing comprising inlet and discharge valve meansl v spaced alongsaid passage and a member that alternately decreases andincreases thecapacity of said tubular member between said valve means having an endengaging said tubular member. 4

16,-In a pump of the character described a body portion having a passagetherethrough hav' ing a lcontinuous rigid fixed wall restrainedvthereof, a plurality of followers mounted for rec P- the crossvsectional area of the passage thereg through beyond normal.

15. In a pump of the character described a body portion having a shaftmounted therein, a single cam on said shaft, said body portion having acontinuous passage extending around said cam in spaced relation thereto,a flexible tubularmember mounted in said'. passage, and means actuatedby said cam reciprocable in said body portion and engaging said tubularmember to rocation in said body portion transversely of s d' passageeach engaging said tubular member -\to vsqueeze the same solely betweensaid followers.

and the xed wall of said passage that is-restrained from any movement,and rotatable means engaging said followers to move the same intosqueezing engagement with said tubular Amember and release thesame topermit said LYNDUS E. HARPER. Y

